Method and Device for Regenerating the Interior Surfaces of Conduits by Means of Thermal Spraying of Metals

ABSTRACT

A method for regeneration of internal conduit surfaces by thermal projection of metals, includes inserting a device including a vehicle having a rolling assembly to permit rolling of the vehicle and carrying a thermal projection system, through a manhole in a conduit installation, including the steps of inserting the device in a conduit with the rolling assembly in a retracted position, and expanding the rolling assembly inside the conduit until the device is centered in the conduit; inserting electrical, pneumatic and/or hydraulic conduits and conduits for supplying metal to be thermally projected, through the manhole, such that the conduits are connected with the vehicle; positioning a regeneration device including the thermal projection system connected with the vehicle by a remote-control pulling system in a particular position to be regenerated; thermally projecting metal from the regeneration device; advancing the vehicle and connected regeneration device to a new regeneration position.

Method and device for regenerating inner surfaces of conduits by meansof thermal projection of metals.

This invention covers a method for treating inner surfaces of conduits,such as conduits of vapour conduction installations, for example, ininstallations for electric energy production; according to said method athermal projection device is deployed, through the end or a manhole of aconduit, and it comprises the operations of positioning, centring,possibly verifying the result, and advancing. It also comprises usingmechanical, optical, acoustic or electronic means for recognition of anychanges in direction of the conduit, and repositioning of the device inrespect of said changes in direction.

This invention also comprises a device for treatment of inner surfacesof conduits which comprises a thermal projection device, pulling means,possibly means for centring a head for projecting particles of moltenmetal, pulling means and possibly a system for detecting any changes indirection of the conduit. The device also comprises means for supplyingenergy and feeding the metal to be projected.

Vapour conduits of all kinds of industrial installations, such as vapourconduits of energy production installations, are subject to aggressionthrough abrasion, due to the high speed at which the vapour circulates,and this can be worsened by possible chemical aggression due to theionisation of the vapour. Over time the abrasion becomes serious and canweaken the conduits. On one hand, these installations areextraordinarily costly, for which reason the replacement of materialwhich can be preserved must be avoided, insofar as this is possible, andon the other, the use of a vapour installation in unsafe conditionsproves highly dangerous, since any pore produced in the conduits, apartfrom a high risk for the safety of any operator who might be affected bythe blast given off, would require immediate stoppage of theinstallation, replacement of the damaged section, and thorough revisionof the entire installation, which would entail very high costs. Sincethere is wear, there has to be a replacement of the material dragged offby the vapour, so as to maintain the initial conditions, or at leastsafe conditions.

STATE OF THE ART

U.S. Pat. No. 6,508,413 describes a machine for cleaning and remotecoating of a conduit, such as a vapour conduit. This machine comprises asupport bar, fitted with associated motors, which comprises motors forthe movement of a head along said bar, and for the rotation of the head,said head comprising means for abrasion cleaning and/or thermalprojection of metal. It comprises at least one pair of tripods forproper positioning and securing in the pipeline and also comprises adevice for control of the device. This device must work in sections,since the device must be repositioned in each of said sections, at thesame time as there are zones, such as the zones for support of thetripod legs, which could lead to shortcomings in the coating, and wouldin any event require the reduction of the distances in which the deviceshas to be relocated in each new section.

This invention refers to a mobile device able to move along a conduit,particularly a horizontal conduit or one with a small slope, whichcomprises:

A moving support; the moving support will be provided with at least onemovement motor and possibly a motor on each of the sides;

A set of means for pulling said moving support along the surface of theconduit; these pulling means can be wheels, chains or pulling bands;

-   -   The pulling means are possibly located more or less radially on        the centre of the device, and preferably said pulling means are        radially extendible for a proper adjustment on the section of        the conduit;

An operating head set in the front part of the moving support;

-   -   The operating head is preferably rotary, normally in a 360° arch        or a little more, said rotation being limited by the cables and        conduits that the device must hold;

A device for thermal projection of particles of molten metal; thethermal projection device is set in the operating head; in turn thethermal projection device can be articulated on the operating head on anaxis transversal to that of the conduit;

At least one means of power supply; the power used can be electricenergy, the power supply means consisting in a cable or set of cablesinserted in the conduits through the manhole or open end of the conduit,as far as the regeneration device, hydraulic energy and/or pneumaticenergy, in these last two cases the corresponding conduits or flexiblehoses would be used;

A means of supplying the metal to be projected, in the form of wire orwire coils;

And possibly:

-   -   A device for detecting the state of the regenerated surface,        understanding state to mean the degree of quality of the coated        surface;    -   A display means;

BRIEF DESCRIPTION OF THE FIGURES

In order to illustrate the following explanation, we are enclosing withthis descriptive report three sheets of drawings in which the essence ofthis invention is represented in six figures, and in which:

FIG. 1 shows a schematic view in perspective of a first more simpleoption of the device for regeneration of inner surfaces of conduits bymeans of thermal projection of metals according to the invention and

FIG. 2 shows a lateral view of the device of FIG. 1;

FIG. 3 shows a lateral schematic view of a second option of the deviceaccording to the invention, in which the body of the device comprisestwo angularly separated sets of wheel, is expandable and extendible tomatch the conditions of the conduit, in a retracted position;

FIG. 4 shows a lateral schematic view similar to the one in FIG. 3, butin an expanded and extended position;

FIG. 5 shows a front view of the device of FIGS. 3 and 4, in which onecan clearly appreciate the angular separation of the wheels; and

FIG. 6 shows a view like the one in FIG. 5, in which the device isfitted with three sets of wheels.

DETAILED DESCRIPTION OF THE PREFERENTIAL FORMS OF EMBODIMENT

This invention therefore consists of a method for regenerating innersurfaces of conduits by means of thermal projection of metals,comprising the stages of:

Inserting a device carrying the thermal projection means through amanhole in a conduit installation; if the carrying device is expandable,the insertion will be performed with the device retracted;

Inserting electrical, pneumatic and/or hydraulic conduits through amanhole, as well as feeding the metal to be thermally projected;

Preferably, when the device is ready for this, the expansion of therolling means to make sure that the device matches the conduit properly;it should normally be ensured that the device is centred in the conduit;

When the device is extendible, the extension of a support of a thermalprojection device;

Movement of the device by remote-control pulling in a particularposition to regenerate until this is positioned in the place to beregenerated, including, where applicable, the corresponding fixing;

The angle alignment of an operating head placed on the carrying device;

The thermal projection of metal from the regeneration device;

Rotation along the surrounding annular perimeter, normally approximately360°, until proper regeneration is achieved, and

advancing to a new regeneration position.

The method also optionally comprises picking up an image of the insideof the conduit and transmitting the information to a device forrecording, viewing or information processing, located on the outside,from which the right decision can be made, such as for a furthermovement of the carrying device to regenerate a new zone, extraction ofthe device, or continuation of the projection process if theregeneration has not reached a satisfactory degree.

The method is also designed to include, as well as or instead of pickingup the graphic image, measuring the thickness of the walls of theconduit or measuring prior to or after the thermal projection phase,determining in either of these cases if the operation has given asufficiently satisfactory result.

This invention also covers a device for regenerating inner surfaces ofconduits by the thermal projection of metals, as claimed in claim 4,which is formed of:

A remote-control vehicle (1), carrying a device for the thermalprojection of metals (4), able to be inserted through a manhole for aninstallation of conduits such as an installation for energy generation;this vehicle (1) comprises, in a preferential embodiment, an elongatedstructure (11) carrying pulling means and a system for carrying a devicefor thermal projection of metal; the vehicle (1) is fitted with a set ofwheels or pulling chains (2); according to the preferential embodiment,the vehicle (1) comprises at least two trains of wheels (22) angularlyseparated by roughly 120°±40°, fitted with at least one front wheel andat least one rear wheel, normally a pair of front wheels and a pair ofrear wheels, at least on of the front or rear wheels or pairs of wheelsis fitted with a drive motor; each front or rear wheel or pair of wheelswill preferably be fitted with a motor with independent drive;optionally, though not preferably, three or more trains of wheels (22)will be fitted, separated from each other at a suitable angle; in thepreferential option each of the trains of wheels is able to be expandedor retracted, so that the dimensions of the device are the very minimumfor inserting into the conduit, to then have the proper operatingdimensions inside the conduit;

An operating head (13) set on the vehicle, normally at the front (theopposite end to where the cables are connected) able to be positionedand angle-aligned properly in respect of said vehicle, comprising adevice for thermal projection (4) of particles of molten metal; inaccordance with a preferential option, the head (13) isextendible/retractile, for example by means of an endless screw (23), sothat when it is in the operating phase the front end of this head willbe at the furthest distance from the body of the vehicle (1); accordingto said preferential option; the operating head (13) is also able torotate on a longitudinal axis; it is desirable for the rotation to takeplace at an angle close to 360°, so that in the thermal projection phasethe regeneration takes place in the same way over the wholecorresponding annular surface;

A device for thermal projection (4); this thermal projection device willnormally be hinged on the operating head (13) on an axis transversal tothat of the conduit;

Electrical (7), pneumatic and/or hydraulic connections for supplying,controlling and manoeuvring the vehicle (1) and the head fitted with thethermal projection device (4) fitted on the remote-control vehicle (1);

A means of supplying the metal to be projected, in the form of wire orwire coils.

The rear end of the vehicle may possibly also comprise a securing device(14) for the cables, wire, or other conduits, and this securing deviceis preferably able to rotate in synchronisation with the operating head(13).

The device according to the invention is designed to also comprise adevice for detecting the thickness and/or the surface evenness of theregenerated surface or also a device for picking up the image inside theconduit and transmitting the information to a device for recording,displaying or information processing.

In accordance with a preferential embodiment, the vehicle (1) comprisesan hinged arm (3), one of whose ends is articulated to this vehicle (1)by means of a lower hinge pin (9) and the other in turn holds theoperating head by means of an upper hinge pin (10). Preferably eitherthe hinged arm (3), or the operating head or both of these comprise arotation axle perpendicular to the corresponding hinge pin (9, 10) whichenables the mobility of the head in the rotational direction (rotationin respect of a vertical axis when the operating head is set in ahorizontal position).

The device disclosed in the invention comprises means of control foradjusting the position of the operating head.

In a preferential embodiment, the device for expanding/retracting thewheel trains (22) takes place by means of a fixed axle (31) (for eachtrain) fitted in the elongated structure (11), as well as acorresponding mobile axle (32) able to be slid along by means of a track(33); as the axles approach each other, the angle of the correspondingcarrying bars in respect of said elongated structure increases, causingthe end where the corresponding wheels are located to move away.

1. Method for regeneration of internal conduit surfaces by means ofthermal projection of metals, which comprises: Inserting a devicecarrying the thermal projection system through a manhole in a conduitinstallation, said device consisting of a vehicle (1) endowed withrolling means; Inserting electrical, pneumatic and/or hydraulic conduitsas well as ones for supplying metal to be thermally projected through amanhole; Placing the regeneration device by means of a remote-controlpulling system in a particular position to be regenerated; and Thethermal projection of metal from the regeneration device. Advancing to anew regeneration position.
 2. A method, according to claim 1,characterised in that the device is inserted into the conduit with thedevice retracted.
 3. A method, according to claim 2, characterised inthat after inserting the device into the conduit, this expands until thedevice is centred in said conduit.
 4. A method, according to any ofclaims 1 to 4, characterised in that if the device is extendible, asupport of a thermal projection device is extended.
 5. A method,according to any of claims 1 to 4, characterised in that it alsocomprises the alignment of an operating head set in a carrying device.6. A method, according to any of claims 1 to 5, characterised in that italso comprises the rotation of the thermal projection device along thesurrounding annular perimeter to a maximum angle of roughly 360°.
 7. Amethod for regenerating the inner surfaces of conduits, according to anyof claims 1 to 6, characterised in that it also comprises picking up theimage of the inside of the conduit and transmitting the information to adevice for recording, displaying or information processing.
 8. A methodfor regenerating the inner surfaces of conduits, according to any of theprevious claims, characterised by also comprising measuring thethickness of the conduit before and/or after the regeneration.
 9. Adevice for regenerating the inner surfaces of conduits by thermalprojection of metals, to carry out the method in claim 1, characterisedby being formed of: A remote-control vehicle (1), carrying a device forthermal projection of metals (4), able to be inserted through a manholeof a conduit installation, such as an installation for energygeneration; An operating head fitted on the vehicle, able to bepositioned and angle-aligned properly in respect of said vehicle,consisting of a thermal projection device (4) Electrical, pneumaticand/or hydraulic connections for feeding, controlling and manoeuvringthe vehicle (1); Electrical, pneumatic and/or hydraulic connections forcontrolling and manoeuvring the thermal projection device (4) fitted ona remote-control vehicle (1).
 10. A device for regenerating the innersurfaces of conduits by thermal projection of metals, according to claim9, characterised in that the remote-control vehicle (1) comprises a setof wheels or pulling chains (2), able to be separately manoeuvred.
 11. Adevice for regenerating the inner surfaces of conduits by thermalprojection of metals, according to claim 10, characterised in that thevehicle (1) comprises an elongated structure (11) fitted with at leasttwo wheel trains (22) angularly separate by roughly 90°±60°, fitted withat least one front wheel and at least one rear wheel and in particularwith a pair of front wheels and a pair of rear wheels, at least one ofthe wheels or pairs of wheels at the front or rear being endowed with adrive motor.
 12. A device for regenerating the inner surfaces ofconduits by thermal projection of metals, according to claim 11,characterised in that the vehicle (1) comprises three trains of wheels(22) separated from each other by an approximately regular angulardistance.
 13. A device for regenerating the inner surfaces of conduitsby thermal projection of metals, according to claim 10, characterised inthat each of the wheel trains is able to be expanded to an operatingposition in the conduit or retracted to a position forinsertion/extraction in said conduit.
 14. A device for regenerating theinner surfaces of conduits by thermal projection of metals, according toclaim 13, characterised in that the device for expansion/retraction ofeach of the wheel trains (22) includes a fixed axle (31) set in anelongated structure (11), as well as a corresponding moving axle (32)able to slide along by means of a track (33).
 15. A device forregenerating the inner surfaces of conduits by thermal projection ofmetals, according to claims 9 to 14, characterised in that the operatinghead (13) set on the vehicle is able to be extended in respect of thebody of the vehicle, and because this operating head is able to rotate amaximum angle of roughly 360°.
 16. A device for regenerating the innersurfaces of conduits by thermal projection of metals, according to claim15, characterised in that the rear of the vehicle (1) comprises asecuring device (14) for the cables, wire or other conduits.
 17. Adevice for regenerating the inner surfaces of conduits by thermalprojection of metals, according to claim 16, characterised in that thesecuring device (14) is able to rotate in synchronisation with theoperating head (13).
 18. A device for regenerating the inner surfaces ofconduits by thermal projection of metals, according to any of claims 9to 15, characterised in that the vehicle also comprises a device fordetecting thickness and/or the surface regularity of the regeneratedsurface.
 19. A device for regenerating the inner surfaces of conduits bythermal projection of metals, according to one of claims 9 to 16,characterised in that the vehicle also comprises a device for picking upthe interior image of the conduit and transmitting the information to adevice for recording, displaying or information processing.
 20. A devicefor regenerating the inner surfaces of conduits by thermal projection ofmetals, according to one of claims 4 to 7, characterised in that thevehicle (1) comprises a hinged arm (3), one of whose ends is hinged tosaid vehicle (1) by means of a lower hinge pin (9) and the other in turnholds the operating head by means of an upper hinge pin (10).
 21. Adevice for regenerating the inner surfaces of conduits by thermalprojection of metals, according to one of claims 4 to 8, characterisedin that the hinged arm and/or the operating head (13) comprises arotation axis perpendicular to the corresponding hinge pin (9, 10). 22.A device for regenerating the inner surfaces of conduits by thermalprojection of metals, according to any